Electrosurgical instruments are well known and widely used in the medical, dental, and veterinarian fields. They offer the capability of precision cutting and coagulation with electrosurgical currents preferably in the megacycle range using a handpiece with, for example, needle, ball, or loop electrodes in a unipolar operating mode or with a forceps in a bipolar operating mode. Ellman International, Inc. makes available an electrosurgical instrument for Radiosurgery which provides on its front panel connectors for receiving the plug of a cable-connected unipolar handpiece and a ground or indifferent plate, as well as connectors for receiving the plug of a cable-connected bipolar electrode. One form of such an instrument is described in U.S. Pat. No. 5,954,686, whose contents are incorporated herein by reference. Such instruments are characterized by different modes and sub-modes of operation. For example, the instrument described in the patent, which is typical of other similar instruments, has a cutting mode, separable into CUT and CUT/COAG sub-modes, and a coagulation mode, separable into HEMO, FULGURATE, and BIPOLAR sub-modes.
In a typical surgical setting using such an instrument, a surgeon may first use a handpiece while the instrument is in its cutting mode to perform a desired cutting procedure and then desire to use the same handpiece for coagulation of blood vessels while the instrument is in its coagulation mode. To this end the electrosurgical instrument has on its front panel push buttons or switches for activating internal circuitry for switching the electrosurgical instrument from its cutting to its coagulation mode or vice-versa. A current electrosurgical instrument contains a power-supply-controlled radio-frequency (RF) oscillator which generates RF currents typically in the megacycle range as high-frequency AC waves. For most cutting purposes, the AC waveform is fully filtered to produce an approximate DC waveform. For most coagulation purposes, the AC waveform is partially rectified (commonly half-wave rectification) to produce the characteristic half-wave rectified waveform. This is accomplished by switching in certain rectifier and filter components for the cutting mode, and switching in certain rectifier components for the coagulation mode. This is well known in the art and further description is unnecessary. Suffice to say, the switching action occurs inside the instrument when the front panel controls are activated by the surgeon.
To simplify mode selection by the surgeon, it is known to place on the handpiece two finger-activated switches that can be connected by appropriate wiring to the electrosurgical instrument and wired in parallel with the front panel switches so that activation of either the finger switches on the handpiece or the front panel switches will allow mode selection. This is similar to the connection and operation of a foot switch that can be used by the surgeon to activate and deactivate the RF currents. More modern electrosurgical instruments, however, do not lend themselves to such a simple approach. The typical modern electrosurgical instrument is computer-controlled, typically by a microcontroller (μC); hence simple parallel-connected circuitry may not work satisfactorily. Another problem is that the standard handpiece has only three terminals, one of which is dedicated to carrying the high-frequency or RF electrosurgical currents; hence, mode selection must be carried out in a safe manner using only two of the three terminals.
A further complication in the use of such instruments is the variety of surgical procedures to which the instrument can be applied, often with different electrodes. Each surgical procedure typically requires not only a particular electrosurgical mode, such as cut or cut/coag, or hemo, but also may require a different set of mode conditions, such as the power setting and/or a different time duration of power application.
With four therapeutic waveforms available in current Radiosurgery instruments and a wide power range, it is time consuming and memory dependent on the part of the surgeon and or staff to tune in the correct waveform and power settings for the particular procedure to be carried out. Also there may have been occasions when electrosurgical injuries may have occurred due to incorrect waveform settings and incorrect power settings for the chosen procedure.